The proton source is where it all starts at CERN. From a compact cylindrical metal unit, small enough to carry, scientists extract the fundamental particles that supply all their experiments.

Protons shoot from the source on the left through the RF quadrupole (copper pipe) into the orange linear accelerator.

To make the protons, physicists inject hydrogen gas into the metal cylinder, then surround it with an electrical field to break down the gas into its constituent protons and electrons. This process yields about 70 percent protons. The particles are accelerated by a 90,000 volt supply and then sent to a radio frequency quadrupole -- an accelerating component that both speeds up and focuses the particle beam. From the quadrupole, the particles are sent to the linear accelerator.